The general objective of the proposed investigations is to evaluate semiquantitatively the effects of a variety of immunologic, pharmacologic and irritant factors on nasal function. Major emphasis will be placed on the effect of pharmacologic agents which are thought to mediate, modulate or block type I hypersensitivity reactions in the nose. Whereas much work is being undertaken in this area with respect to bronchial asthma, little information has been accrued in regard to allergic rhinitis; and preliminary data from this laboratory suggest the possibility of important differences between the two diseases. Agents for study include isoproterenol, propranolol, phenylephrine, methacholine, atropine, histamine, cromolyn sodium and an antihistamine. The effect of these substances will be evaluated primarily by measurements of nasal airway resistance employing techniques and equipment developed in this laboratory. Some comparisons will be made between the responses of atopic and nonatopic individuals. The capacity of several agents to block the response to pollen challenge in sensitive subjects will be ascertained. Likewise, gaseous and particulate irritants will be studied in respect to "priming" pollen responses and blocking irritant reactions by various agents.